Safety anchorages for controlling pay-out of a safety line

Abstract

A fall-arrest safety anchorage has a safety line drum 10 and braking mechanism assembled to a spine plate (1). The braking mechanism comprises a rotatable brake component (2) and fixed brake components (1,7) which are relatively rotated against a frictional resistance on engagement of a centrifugal clutch if the unwinding speed of the drum exceeds a certain value. The clutch comprises coupling elements (17) and abutments (16) which lie within or extend into an aperture in the spine plate (1).

I claim: 
     
       1. A fall-arrest safety anchorage including: load bearing spine means (1,26,65,155), having at least one attachment point (1a; 271; 140a; 155a) by which it can be attached to a fixture;   a safety line drum (10,62,143) from which a safety line can be drawn in response to a pulling force on that line exerted by a body attached thereto,   braking means for arresting rotation of the drum, said braking means including relatively rotatable brake components (2; 22,26; 65; 144,148; 155),   means for imparting frictional resistance (5,6; 145,146) to relative rotation of said relatively rotatable brake components,   clutch means (16,17,22; 140,149-151) which functions automatically to cause relative rotation of the relatively rotatable brake components against said frictional resistance means on rapid acceleration of the safety line drum such as occurs in the event of a fall of a person attached to the safety line,   said clutch means including coupling elements (17; 150) which are displaceably connected to the safety line drum, abutments (16; 151) with which said coupling elements move into engagement so as to bring about the relative rotation of the brake components,   said safety-line drum and said braking means are carried by the load-bearing spine means,   said load-bearing spine means consisting of a single spine plate (1; 26; 65; 140; 155) having an annular aperture;   said single spine plate serving to transmit load and braking forces operating on the safety anchorage to said at least one attachment point, and   said coupling elements (17; 150) and the abutments (16; 151) being so located that they engage within the aperture in said spine plate.   
     
     
       2. A safety anchorage according to claim 1, wherein said abutments (16) are provided on a rotatable one (2; 22) of said relatively rotatable brake components (1,2 22, 65; 155) and said frictional resistance means (5,6) functions between that rotatable component and said spine plate (1;26;65; 155), the spine plate serving as a fixed brake component. 
     
     
       3. A safety anchorage according to claim 2, wherein said abutments (16) are distributed around the paths along which said coupling elements (17) move during rotation with the safety line drum, an outer marginal portion of said rotatable brake component (2; 22) overlaps a portion of the spine plate (1; 26;65; 155) surrounding said spine plate aperture, and said frictional resistance means (5,6) functions between overlapping portions of that brake component and spine plate. 
     
     
       4. A safety anchorage according to claim 1, wherein the clutch means coupling elements (149) are carried by a brake component (144) which is mounted so that it rotates with the safety line drum (143) so long as the clutch means is inoperative, said frictional resistance means (145,146) functions between said brake component and the safety line drum; and said abutments (151) are provided on said spine plate so that engagement of said coupling elements with the abutments arrests motion of said brake component. 
     
     
       5. A fall-arrest safety anchorage including: load bearing spine means (1,26,65,155), having at least one attachment point (1a; 27 a; 140a; 155a) by which it can be attached to a fixture;   a safety line drum (10,62,143) from which a safety line can be drawn in response to a pulling force on that line exerted by a body attached thereto,   braking means for arresting rotation of the drum, said braking means including relatively rotatable brake components (2; 22,26; 65; 144,148; 155),   means for imparting fictional resistance (5,6; 145,146) to relative rotation of said relatively rotatable brake components,   clutch means (16,17,22; 140,149-151) which functions automatically to cause relative rotation of the relatively rotatable brake components against said frictional resistance means on rapid acceleration of the safety line drum such as occurs in the event of a fall of a person attached to the safety line,   said clutch means including coupling elements (17; 150) which are displaceably connected to the safety line drum, abutments (16; 151) with which said coupling elements move into engagement so as to bring about the relative rotation of the brake components,   said safety-line drum and said braking means are carried by the load-bearing spine means,   said load-bearing spine means including at least one spine plate (1; 26; 65; 140; 155);   said spine means serving to transmit load and braking forces operating on the safety anchorage to said at least one attachment point, and   said coupling elements (17; 150) and the abutments (16; 151) being so located that they engage within an aperture in said spine plate, aid abutments are provided on a rotatable one of said relatively rotatable brake components and said frictional resistance means functions between that rotatable component and said spine plate, the spine plate serving as a fixed brake component, and wherein a portion of said rotatable brake component on which said abutments are provided includes a rib with a smooth exterior peripheral surface which makes a close sliding fit in said spine plate aperture so that the spine plate forms a bearing for said rotatable brake component.